Microstructure, carbides and mechanical properties of 7Cr17MoV stainless steel used as cutlery material produced by hot rolling and cold rolling were studied. The experimental results demonstrate that the microstructure of the rolled steel consists of spheroidal pearlite and carbides. During hot rolling process, the carbides will aggregate obviously and the size of carbides is almost above 2 μm. Then after cold rolling, the aggregation of carbides disappear, and the carbides become fine and uniformly distributed, at the same time, there are some nanoscale carbides. During cold rolling process, the vanadium carbides and molybdenum carbides will decrease and disappear and the carbides mainly consist of (Fe, Cr)23C6. Tensile strength of the cold rolled thin strip (0.7 mm) is about 690 MPa. The dimples and the second phase particles can be easily seen in the tensile fracture, and the second phase particles are identified to be mainly carbides and inclusions.

As the key procedure during steelmaking process, the production in steelmaking plant involving four processes: hot metal pretreatment, steelmaking, secondary refining and continuous casting. Such as steelmaking process, the fine production in steel manufacturing process was described. Fine production for steelmaking process is elaborated from the fine control of productive technology, the fine configuration and operation of process facilities, the fine control of production process. Meanwhile, recent research progress concerning fine production for steelmaking process was reviewed. Fine production for steelmaking process was of great importance to the high quality, high efficiency, low cost, and energy saving production in steel manufacturing process.

The morphology of the reduction products of Fe-Cr-O systems by C at different temperatures and time intervals was studied in this paper. The samples include two systems of FeCr2O4+C and Fe2O3+2Cr2O3+C. It is found that the reduction degrees of the two samples increase with increasing temperature, and the reduction degree can be above 90% when the reaction is close to balance. The reduction processes of FeCr2O4 and Fe2O3-Cr2O3 are similar and the final reduction products are composed of Fe-Cr-C alloys and metal carbides (mainly Cr7C3). A method was proposed to estimate the contents of Fe-Cr-C alloys and metal carbides in the final reduction products, and the estimated results agree with the calculated data. It is shown that the content of Fe-Cr-C alloys increases while the content of metal carbides decreases with increasing temperature, and the composition of Fe-Cr-C alloys varies with temperature.

The mathematical models of blast furnace (BF) hearth were established and the masonry structures of large carbon blocks and small carbon bricks for hearth were discussed from the view of heat transfer. The temperature of these two hearth structures during BF drying process were calculated as well as after blow-in. It is found that the filling between staves and carbon bricks can not be dried effectively at present BF drying conditions and the thermal conductivity of filling can not reach the designed value. Moreover, with the existing of filling, the hot face temperature of lining is higher which results in more serious erosion. Therefore, the filling should be cancelled between staves and carbon bricks. It has obvious advantage of heat transfer for carbon bricks touching with staves directly. The hearth structure of small carbon bricks could be designed to touch with staves directly so that it exterminates the barriers on heat transfer of hearth. The hearth structure of large carbon blocks should be put some small carbon bricks touch with staves directly and then make the filling between the small carbon bricks and large carbon blocks. The filling moves towards center of BF more than about 200 mm. In order to dry filling completely during BF drying process, the necessary method is without utilizing cooling water. Meanwhile, some measures are discussed for keep staves safe.